package com.shuaixin.web.util;

public class Distance {
	private static final double EARTH_RADIUS = 6378137;
	private static double rad(double d){
		return d * Math.PI / 180.0;
	}
	 public static double GetDistance(double lng1, double lat1, double lng2, double lat2)
	 {
	    double radLat1 = rad(lat1);
	    double radLat2 = rad(lat2);
	    double a = radLat1 - radLat2;
	    double b = rad(lng1) - rad(lng2);
	    double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) + 
	 	Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
	    s = s * EARTH_RADIUS;
	    s = Math.round(s * 10000) / 10000;
	    return s;
	 }
	 
	    public static void main(String[] args)
	    {
	    // TODO �Զ����ɷ������
	        double distance = GetDistance(121.491909,31.233234,121.411994,31.206134);
	        System.out.println("Distance is:"+distance);
	    }
}
